Rome had changed. The people of Rome had changed. They were tired of being ruled by others. They wanted to rule themselves. So after years of fighting against the last king of Rome, Tarquin the Proud, the people of Rome created a new form of government. It was called a republic. In a republic every citizen voted for leaders who would create their laws.
In the Roman republic every citizen could vote for their leaders, but who were the citizens? Only adult free men could be citizens! That meant women, children and slaves were not citizens, and could not vote.
The new Roman Republic wanted everyone to know what the laws were. They also wanted to make sure that the law applied to everyone rich and poor alike. So they engraved the law on tablets of metal and put them in the forum for everyone to read. They remained there, on display, throughout the time period that Rome was a republic. These laws were called the Twelve Tables because there were twelve different sections. These laws were about crime and property and family matters like marriage and inheritance.
It didn't matter if you were rich or poor; the law applied to every citizen.